Theory and experiments support that plant invasions largely impact aboveground biodiversity and function. Yet, much less is known on the influence of plant invasions on the structure and function of the soil microbiome of coastal wetlands, one of the largest major reservoirs of biodiversity and carbon on Earth. We studied the continental‐scale invasion of Spartina alterniflora across 2451 km of Chinese coastlines as our model‐system and found that S. alterniflora invasion can largely influence the soil microbiome (across six depths from 0 to 100 cm), compared with the most common microhabitat found before invasion (mudflats, Mud). In detail, S. alterniflora invasion was not only positively associated with bacterial richness but also resulted in important biotic homogenization of bacterial communities, suggesting that plant invasion can lead to important continental scale trade‐offs in the soil microbiome. We found that plant invasion changed the community composition of soil bacterial communities across the soil profile. Moreover, the bacterial communities associated with S. alterniflora invasions where less responsive to climatic changes than those in native Mud microhabitats, suggesting that these new microbial communities might become more dominant under climate change. Plant invasion also resulted in important reductions in the complexity and stability of microbial networks, decoupling the associations between microbes and carbon pools. Taken together, our results indicated that plant invasions can largely influence the microbiome of coastal wetlands at the scale of China, representing the first continental‐scale example on how plant invasions can reshuffle the soil microbiome, with consequences for the myriad of functions that they support.

As a dominant mangrove species, Kandelia obovata is distributed in an intertidal marsh with an active H₂S release. Whether H₂S participates in the salt tolerance of mangrove plants is still ambiguous, although increasing evidence has demonstrated that H₂S functions in plant responses to multiple abiotic stresses. In this study, NaHS was used as an H₂S donor to investigate the regulatory mechanism of H₂S on the salt tolerance of K. obovata seedlings by using a combined physiological and proteomic analysis. The results showed that the reduction in photosynthesis (Pn) caused by 400 mM of NaCl was recovered by the addition of NaHS (200 μM). Furthermore, the application of H₂S enhanced the quantum efficiency of photosystem II (PSII) and the membrane lipid stability, implying that H₂S is beneficial to the survival of K. obovata seedlings under high salinity. We further identified 37 differentially expressed proteins by proteomic approaches under salinity and NaHS treatments. Among them, the proteins that are related to photosynthesis, primary metabolism, stress response and hormone biosynthesis were primarily enriched. The physiological and proteomic results highlighted that exogenous H₂S up-regulated photosynthesis and energy metabolism to help K. obovata to cope with high salinity. Specifically, H₂S increased photosynthetic electron transfer, chlorophyll biosynthesis and carbon fixation in K. obovata leaves under salt stress. Furthermore, the abundances of other proteins related to the metabolic pathway, such as antioxidation (ascorbic acid peroxidase (APX), copper/zinc superoxide dismutase (CSD2), and pancreatic and duodenal homeobox 1 (PDX1)), protein synthesis (heat-shock protein (HSP), chaperonin family protein (Cpn) 20), nitrogen metabolism (glutamine synthetase 1 and 2 (GS2), GS1:1), glycolysis (phosphoglycerate kinase (PGK) and triosephosphate isomerase (TPI)), and the ascorbate–glutathione (AsA–GSH) cycle were increased by H₂S under high salinity. These findings provide new insights into the roles of H₂S in the adaptations of the K. obovata mangrove plant to high salinity environments.

Avicennia marina, a mangrove plant growing in coastal wetland habitats, is frequently affected by tidal salinity. To understand its salinity tolerance, the seedlings of A. marina were treated with 0, 200, 400 and 600 mM NaCl. We found the whole plant dry weight, photosynthetic parameters increased at 200 mM NaCl but decreased over 400 mM NaCl. The maximum quantum yield of primary photochemistry (Fv/Fm) significantly decreased at 600 mM NaCl. Transmission electron microscopy observations showed high salinity caused the reduction in starch grain size, swelling of the thylakoids and separation of the granal stacks and even destruction of the envelope. In addition, the dense protoplasm and abundant mitochondria in the secretory and stalk cells, and abundant plasmodesmata between salt gland cells were observed in the salt glands of the adaxial epidermis. At all salinities, Na⁺ content was higher in leaves than in stems and roots, however, Na⁺ content increased in the roots while it remained constant level in the leaves over 400 mM NaCl treatment, due to salt secretion from the salt glands. As a result, salt crystals on the leaf adaxial surface increased with salinity. On the other hand, salt treatment increased Na⁺ and K⁺ efflux and decreased H⁺ efflux from the salt glands by the non-invasive micro-test technology, although Na⁺ efflux reached the maximum at 400 mM NaCl. Further RT-qPCR analysis indicated that the expression of Na⁺/H⁺ antiporter (SOS1 and NHX1), H⁺-ATPase (AHA1 and VHA-c1), K⁺ channel (AKT1, HAK5 and GORK) were up-regulated, only Na⁺ inward transporter (HKT1) was down-regulated in the salt glands enriched adaxial epidermis of the leaves under 400 mM NaCl treatment. In conclusion, salinity below 200 mM NaCl was beneficial to the growth of A. marina, and below 400 mM, the salt glands could excrete Na⁺ effectively, thus improving its salt tolerance.

Hydrogen sulfide (H₂S), is a crucial biological player in plants. Here, we primarily explored the interaction between sodium hydrosulfide (NaHS, a H₂S donor) and the fluxes of Na⁺ and K⁺ from the salt glands of mangrove species Avicennia marina (Forsk.) Vierh. with non-invasive micro-test technology (NMT) and quantitative real-time PCR (qRT-PCR) approaches under salinity treatments. The results showed that under 400-mM NaCl treatment, the addition of 200-μM NaHS markedly increased the quantity of salt crystals in the adaxial epidermis of A. marina leaves, accompanied by an increase in the K⁺/Na⁺ ratio. Meanwhile, the endogenous content of H₂S was dramatically elevated in this process. The NMT result revealed that the Na⁺ efflux was increased from salt glands, whereas K⁺ efflux was decreased with NaHS application. On the contrary, the effects of NaHS were reversed by H₂S scavenger hypotaurine (HT), and DL-propargylglycine (PAG), an inhibitor of cystathionine-γ-lyase (CES, a H₂S synthase). Moreover, enzymic assay revealed that NaHS increased the activities of plasma membrane and tonoplast H⁺-ATPase. qRT-PCR analysis revealed that NaHS significantly increased the genes transcript levels of tonoplast Na⁺/H⁺ antiporter (NHX1), plasma membrane Na⁺/H⁺ antiporter (SOS1), plasma membrane H⁺-ATPase (AHA1) and tonoplast H⁺-ATPase subunit c (VHA-c1), while suppressed above-mentioned gene expressions by the application of HT and PAG. Overall, H₂S promotes Na⁺ secretion from the salt glands of A. marina by up-regulating the plasma membrane and tonoplast Na⁺/H⁺ antiporter and H⁺-ATPase.

Background/Objectives: Grapes (Vitis vinifera), particularly ‘Shine Muscat’, are prone to postharvest quality loss mainly due to poor storage tolerance. Actinomycetes are microbial resources that produce secondary metabolites that exhibit notable functional properties. Methods: This study explored the use of Streptomyces albulus Ah11601 fermentation broth (SFB) as a postharvest treatment to preserve ‘Shine Muscat’ grape quality during 6 days of room temperature storage using physiological, transcriptomic, and bioinformatics analyses to elucidate the underlying regulatory mechanism. Results: The results demonstrated that, compared to the control group stored at room temperature (25 °C) for 6 days (6D), the SFB-treated group (T6D) presented a significant delay in the decrease in fruit hardness and vitamin C content. Further investigations revealed that the 6D treatment significantly elevated lipoxygenase activity, MDA content, O₂⁻ generation rate, and H₂O₂ levels. In addition, both the 6D and T6D treatments significantly increased the activities of SOD and APX. Functional enrichment analysis revealed that the upregulated DEGs in the 6D group were predominantly enriched in pathways such as phenylpropanoid biosynthesis; flavonoid biosynthesis; phenylalanine metabolism; and stilbenoid, diarylheptanoid, and gingerol biosynthesis. The downregulated DEGs were enriched primarily in the endoplasmic reticulum protein processing pathway. In the T6D group, the upregulated DEGs were predominantly enriched in the zeatin biosynthesis pathway. In addition, significant alterations in the expression of genes associated with the ethylene and abscisic acid signaling pathways were detected. Conclusions: In conclusion, SFB treatment effectively mitigated the deterioration of the postharvest quality of ‘Shine Muscat’ grapes by preserving the cellular redox balance, regulating cytokinin and ethylene biosynthesis, and optimizing the regulation of ethylene and abscisic acid signaling.